Treatment of hydrocarbon oils



Patented Apr. Y

NITD;

marmi' or mnoomon olLs Gustav Eglo, Oil Products tion of Delaware Chicago, Ill., aldgnor to Universal Company. Chicas., lll., s corron- Appli-cation Maren 21, im, sel-n1 No. 325,1

" comms. minus-1mV This invention relatesA to the catalytic treatment of intermediate honing range fractions prolysts in substantially anhydrousv condition may I be admitted to a pump 8 from a line i containing duced in the primary lnon-#cracking distillation of I petroleum although similar or analogous material l from other sources may also be treated.

More specifically the invention has reference to a method whereby gas oils are treated in a series of cooperating steps with the object of ultimately producing relatively high yields of iso-paramns which are utilizable directly as aviation fuel or inblend with gasolinesinferior in anti-knock value to improve their quality. 'A

It has come to be recognized thatthere'are limitationsv to Iboth yield-and Vquality of motor fuels producible by the thermal treatment of petroleumv fractions and also-that there are some limitations to the yields and types oi motor fuels.

obtainable when catalysts are employed. The present process. involves primarilythe catalytic cracking of gas oil fractions with primary fractionation of the products r`and the selective thermal .cracking of certain gaseous fractions to produce olefinsfor alkylatin'g other originalgaseous fractions, this combination of steps leading ultimately to the yproduction .of higher antiknock' saturated gasoline fractions of an iso c .character than are pnoduclble by processes i11- volvin'g .merely'thermal or catalytic cracking in a single stage type of operation.

' In one speciiic embodiment the present invention Ycomprises subjecting intermediate boiling .range hydrocarbon fractions to thermal treatment in the presence of catalysts comprising fer' a valve 'I in suspension in .an oil whichvmay he a portion of the charging oil admitted to pump 3 or 'i may be an-oil of a different character, pump 8 discharging through a line 9 containing valve Il y into they line! so that Ithe catalyst is slurried in charging stock passing through the heating element. Insuiiiciently converted materials are returned to line l by way of line I9 as willbe presently described.

The object of the first catalytic cracking step is. to produce as high yields of butanes as possiblev and a unit is therefore preferably operated at a relatively high recycle ratio, the temperature employed at the exit of heater coll I I being of -th order of 500-700 F., depending upon rthe character of the stock being processed while any desired Pressure may be, maintained with the vobject of ric chloride and aluminum chloride. to producel relatively high' .yields of butanes, fractionating the products to. produce a normal butane fraction and an isoQ-butane fraction', thermally cracking said normal butanefraction to produce high yieldsof'oleilns of 2,l 3, and 4i carbonv atoms to.

the molecule, and alkylatlng iso-lbutane with the oleilns thus` produced in the presence ofselcctcd'4 catalysts.

controlling the time factor and the rate and char-V acter of the reaction. .I have found that at a high recycle ratio and moderatetemperatures of operation high yields of butanes butaneis considerably less than the production of iso-butane so that 'there is need .for introducing 4oleilnic materials fromoutside sources if the iso-huta'ne production is to' be completely alkillated. 'v

The heated through/line I'Seontalning valve Hand intof a fractionator II of suitable design'and 'construcf The-processor the invention mayconveniently be vdescribed in connection with @heattached drawing which shows diagrammatically in gen1.y

eral side elevation a combination of interconnected apparatus in which 'the process may he-- carried out. v l

Referring to the drawing, may be ad- .mitted to acharging pump-I byway ofa line I v'tiontoperrnit the eilicient separation of xed .gases having a. lower molecular weight than butanes which are released -through line 2| con- .taimngvalvelI-and disposed of in any desired manner'and to permit the separate production of" iso-butane andof normal butane which are indicated as being removed from the fractionator as containing valve I, pump I through line4 4 containing valve i .into and through a heating element `I Iv disposed to receive heat. from a` l furnace I2.

Ferrie chloride and/or aluminum chloride cataindividual'-side-cuts. `Inactual practice, however, a considerably more complicated fractionatlng system will be necessary to insurethe separation oi'iso-butane and normal butanes which'may 'involve use of several fractionating columns with one particularly designed to handle and fractionate hydrocarbons having live carbon atoms are produced .which constitute stocks for further treatment to materials from heater II .I

and less tothe molecule. As shown in the drawing an iso-butane fraction boiling at approximately F. is shown diagrammatically as being removed from an accumulator plate 23 by way of line 25 containing valve 26 and passed to an alkylation unit which will be presently described.

, From the same fractionator a lower accumulator plate 24 is indicated as furnishing normal butane which is withdrawn throughline 3l containing valve 3i and thermally cracked to produce oleiins for the alkylation of the i-butane. If desired a high antiknock aviation gasoline fraction may be removed as a side-cut from the fractionating column. Insuiliciently converted refiuxes are withdrawn from the bottom of fractionator i5 through line i6 containing valve Il to a recirculating pump I8 which discharges through line I9 containing valves 2l and 2l' and back to line 4 as previously described. The reflux removed at this point will contain partly spent metal halide catalysts which may be continuously withdrawn in part through valve while fresh catalyst is introduced through line 6 as makeup. By proper manipulation and withdrawal of a certain proportion of the spent material formation of catalyst sludges and coky residues can be substantially prevented. The use of proportioned mixtures of ferrie chloride and aluminum chloride is preferred since the ferrie chloride moderates the activity of the aluminum chloride and permits the production of relatively higher yields of the desired butanes. I

It is preferable to have present relatively small amounts of hydrogen chloride which may be added along with the original slurry of catalysts or which may be separately injected into the line conveying the catalyst and oil to be treated to the heating and fractionating zones although means for this purpose are not indicated in the drawing.

Similarly, recirculation apparatus used conventionally to return a portion of overhead condensate to the top of fractionator I5 to control and gulate the fractionation therein have not been own.

A normal butane fraction from line Il is taken' by pump 32 and discharged through line Il containing valve into and through the heating V element :I5 arranged to receive heat from a furnace 38. If necessary the normal butane fraction may be cooled and liqueed in order to prevent difficulties in the operation of pump 32. The conditions which have been found to be optimum for cracking normal butane to produce particularly high yields of butenes have been found to temperatures of the order of 9001200 F. and fines at reaction temperature of the order of t-l5". Under these conditions as will be shown in later examples, yields of butenes as high as 20% per pass (based on n-butane decomposed) are obtainable along with production of ethylene and propylene and other gases..

The heated and converted materials from heating element Il pass through line l1 containing valve 3l (preferably with quenching to stop undesirable reactions) to fractionator 3l which represents fractionating equipment of a suitable design and construction to permit the production of relatively short individual gaseous fractions.

For example. the fractionating system is prefer' ably operated to produce an incondensible gas containing all those lighter than ethylene which are'released through line 42 containing valve 43.

mulator plates I1, Il and Il accumulate propene, iso-butene, and normal butene fractions respectively which are withdrawn through line Il containing valve ,line Il containing valve 52 and line I4 containing valve 55.- Fractionator 3l is provided with a bottom draw line 4l containing a valve 4i for the removal of heavy maxiaL InV y iso-butane so that the most general practice is to add some olefin-containing gases from an outside y source such as those produced in an ordinary thermal cracking process. For this purpose line 31' containing valve Il' is indicated as a point of entrance for such gases prior to the fractlonator :s and une n' containing valve 2|' is molested as an alternate point of introduction directly prior to the alkylation step.

It is comprised within the scope of the present `invention to alkylate the separated 4isobutane with any or all of the oleflnic hydrocarbons, produced in the cracking of a normal butane. l However, in the interest of simplicity the description of the process given in connection with the drawing willl be limited to the alkylation of the iso-butaneI with the combined olefin production which is passed through line I6 to line 2l leading to line 5l which admits alkylating catalysts which may be sulfuric acid, 'el-ther cold or hot, hydrogen fluoride, boron fluoride, aluminum chloride alone or on supports or other eilicient catalysts. these being. introduced through line it containing valve 51 to catalyst pump Il which discharges througllrline 59 containing valve Il, into the stream of ed olefln-is'o-butane hydrocarbons. Sincealkylation reactions are generally of an exothermic character the reactants and catalyst are preferably cooled during passage through a cooling coil il disposed in a cooler 62 and then passed through line il containing valve Il through an alkylator 65 wherein time is given for the effecting of the desired alkylation reaction. ciated that the alkylation unit comprising broadly cooler 62 and alblator is only diagrammatic and that different modes of operation may be employed. For example, in addition to the flows shown in the drawing a granular alkylation catalyst such as, for example. aluminum chloride supportedon a porous granular. material such as activated carbon may constitute filling material for the alhlator and the necessity for separation of this catalyst from the reaction products is thereforeobviated. Furthermore. in any type of alkylation the apparatus -may be employed in multiple connection where catalyst recovery is An accumulator plate Il may then accumulate an ethane-ethylene fraction which is withdrawn necessary in order to insure the continuity of the operation.v The reactants' passing through line It containing valve 01 pass to a receiver and separator wherefrom separated gases may be withdrawn through line t! containing valve Il and separated and partly spent catalyst may be returned by way of line Il containing valve 12 to pump I3 and discharge line Il containing valve 15 back to line Il for further use. A portion of spent catalyst may be discharged conthrough line 45 containing valve 4I while accu- 75 tinuously or intermittently through line 'I4' and It will be appre-` into and through a heating element 8| disposed valve 'II' rwhile maken' is supplied through une u..

of the invention to separately alkylate individual fractions of iso-butane with ethylene, propylene,

iso and normal butylene. When alkylating with ethylene thermal reaction may be brought about at temperatures of the order of 950 1i'. and pres.

sures of the order of 1000-5000 lbsJsqin. to produce neo-hexane, and similar results may be obtained using milder conditions of operation and hydrogen fluoride and/or boron fluoride catalysts. When alkylating with propene, it is preferred to use hydrogen fluoride catalysts; when alkylating with iso-butene or normal butene,.it

4is preferred to employ sulfuric acid of approxii 3 csc' F. at an exit orthe heating element of the catalytic cracking unit.l A Y The normal butane product is-subiected to pyrolysis to produce therefrom about 50% of a mixture of oleiins comprising ethylene, propene, iso-butane, and normalbutene and to supplement the olefin productionthe mixture of gases obtained in the stabilization of a crackednaphtha and comprising 40% by volume of mixed normally gaseous olefins `is introduced in suillcient v quantity to provide'an amount of oleilns approximately equivalent to those produced in the thermal treatment of a normal butane. The isobutane is thereupon alkylated in the presence of mately 90-100% concentration and normal atmospheric temperatures, say from 1030 C. When us'ing phosphoric acid and particularly the so-called solid phosphoric acid catalysts, the best alkylation results are obtained when' using temperatures of the order of approximately 200-400. C. and lpressures of the order of 2000-5000 lbs/soin. not claimed individually in the present4 process but'I only in 'combination with the liso-h'eptanes, and iso-octanes. To separate these compounds, the products' of the alkylationare withdrawn from accumulator 0I through line 16 containing valve 11 to a pump 'Il which discharges through a -line 10 containing avalve l0 to receive heat from a furnace l2 in which suiiicient heat is imparted to the alkylate lso that it can be fractionated. The heated materials passing through aline I3 containing valve Il to .a

fractionator 85 having a bottom `draw line 86 containing a valve l1 for the removal of heavier /alkylated material than is desired in the nal product or products. As-shown in the drawing. vapors fromy fractionator II pass through vapor line 88 containing valve I9 through a condenser 90, the cooled material passing through run-down 1lne'9l containing valve 92 to a iinal receiver 93 for finished product. This receiver has a conventional gas release line 84 containing a valve 95 and a line for the desired liquid product 96 containing valve 91. It is obviously withinthe scope of the invention to operate fractionator I5 to produce a series of side cuts consisting of fractions predominating in some of theindividual` hydrocarbons produced as the result of the sep-l -arate or combined alkylation reactions.

, The following illustrative example is introduced at this point to show the type of results and yields of products to be normally expected in the lpractical operation of the process although the 4produced lapproximately 35% by weight of isobutane and 10% by weight of normal butane v treatment at an elevated temperature and pres-- sulfuric acid at a temperature of 70 F. so that there is ultimately produced from the gasv oil charge, a mixture consisting essentially of isoparaillnic hydrocarbons boiling within the approximate range of 100400 F. and showing an octane number. of 85 by the motor method. In the alkylation step an excess of iso-butane is maintained at `all times to limit the tendency toward polymerization and ester formation among the oleilns. v

I claim as my invention: 1

v1. A process for treating petroluem fractions to produce therefrom substantial yields of essentiallyparaiiinic motor fuel having relatively high antiknock value which comprises'subjecting an intermediate boiling range petroleum fractionto -sure in the presence of a catalyst consisting essentially of a -mixture of ferrie chloride and aluminum chloride with a minor amount of hy- .drogen chloride to Iproduce a substantial yield of iso-butane andv normal butane, separating said iso-butane and said normal butane, thermally cracking said normal butane at an elevated temperature and pressure and for a time of reaction adequate to produce a substantial yield of oleilnic hydrocarbons, alkylating said iso-butane with said oleiinic hydrocarbons and fractionating the products of the alkylation step to recover high anti-knock value gasoline.

while utilizing a temperature oi?l approximately 2. A process for treating-petroleum fractions to produce therefrom substantial yields of essentially parafllnic motor fuel having relatively high antiknock value which comprises subjecting an intermediate boiling range petroluem fraction 50 to treatment at an elevated temperature of the order of 50o-700 F. and a superatmospheric pressure in the presence of a catalyst comprising` Vessentially a mixturev of ferrie chloride and alu? minum chloride with a minor amount of hydrogen chloride to produce a substantial' yield of iso-butane -and normal butane, separating said iso-butaneand said normal butane,` thermally cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to produce a substantial yield of olefinic hydrocarbons, alkylating said isobutane with said oleiinic hydrocarbons and fractionating the products of the alkylation step to produce high antiknock value gasoline.

3.4 A process for treating petroluem fractions to produce therefrom substantial yields of essentially paraillnic motor fuel having relatively high antiknock value ,which comprises subjecting an intermediate boiling range petroleum fraction to treatment at an elevated temperature of the order of 500400 F. anda superatmospheric pressure in the presence oi.'v a catalyst comprising essentially a mixture oi' fer'ric chloride and aluminum chloride with 'a minor amount of hydrogenchloride to producesubstantial yields of isobutane and normal butane, separating said isobutane and said normal butane, thermally cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to produce a substantial yield of oleflnic hydrocarbons, alkylating said iso-butane with said olenic hydrocarbons and similar hydrocarbons introduced from a source extraneous to the process, and fractionating the products of the alkylation step to recover the resultant high cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to produce a substantial yield of oleilnic hydrocarbons, alkylating said iso-butane with said olenic hydrocarbons and similar hydrocarbons introduced from a source extraneous to the process, in the presence of sulfuric acid of approximately S90-100% concentration, and fractionating recover the resultant high antiknock valuegasoline. s f

5. A process for treating petroleum fractions the products of the alkylation stepto,

to produce therefrom substantial yields of essentially paraiiinic` motor fuel having a relatively high antiknock value which comprises subjecting an intermediate boiling range petroleum fraction to treatment at an elevated temperature of the order of 50G-700 F. and a superatmospheric pressure in the presence of a catalyst comprising essentially a mixture of fenic chloride and aluminum chloride with a minor amount of hydrogen chloride to produce substantial yields of iso-butane and normal butane;` separating said iso-butane and said normal butane, thermally cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to produce a substantial yield of oleilnic hydrocarbons,. alkylating said iso-butane with said olellnic hydrocarbons and similar hydrocarbons introduced from a source extraneousto the process in the presence of a granular phosphoric acid-containing catalyst and fractionating the products of the alkylation step to produce the desired high anti-knock value gasoline.

6'. A process for treating petroleum fractions to produce therefrom substantial yields of essentially parafilnic mlotor fuel having relatively high antiknock value which comprises subjecting an intermediate boiling range petroleum fraction to treatment at an elevated temperature of the order of 50G-700 F. and a super-atmospheric pressure in the presence of a catalyst consisting essentially of a mixture of ferric chloride and aluminum chloride with a minor amount of hydrogen chloride to produce substantial yields of iso-butane and normal butane, separating said iso-butane and said normal butane, thermally cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to produce a substantial yield of clenic hydrocarbons, alkylating` said iso-butane with said oleiinic hydrocarbons and similar hydrocarbonslntroduced from a source extraneous to the process in the presence of sulfuric acid of approximately -100% concentration at a temperature of the order of 10-30" C. and fractionating the products of the alkylation step to recover the resultant high antlknock value gasoline.

7. A process for treating petroleum fractions to produce therefrom substantial yields of essentially paraiiinic motor fuel having a relatively high antiknock value which comprises subjecting an intermediate boiling range petroleum fraction to treatment at an elevated temperature of the order of 500-700 I". and a superatmospheric pressure in the Apresence of a catalyst comprising essentially a mixture of ferrie chloride and aluminum chloride with a minor amount of hydrogen 'cmoride to produce substantial yields or :lso-butane and normal butane, separating said iso-bu- 'tane and said normal butane, thermally'cracking said normal butane at an elevated temperature under pressure and for a time of reaction adequate to producev a substantial yield of oleiinlc hydrocarbon, alkylating said iso-butane with said oleiinic hydrocarbon and similar hydrocarbon introduced from'a source .extraneous to the process in the presence of -a granular phosphoric acidcontaining catalyst at a temperature of the order of 200-400 C. and a pressure of the order of 2000-5000 pounds per square inch and fractionating the products of the alkylation step to recover therefrom hlgh antiknock value gasoline.

8. A process for treating petroleum fractions to produce therefrom substantial yields of neo-hexane which comprises subjecting an intermediate boiling range petroleum fraction to treatment at j a temperature of the order of 50o-700 F. and a superatmospheric pressure in the presence of a catalyst comprising essentially a mixture of ferric chloride and aluminum chloride with a minor amount of hydrogen chloride to produce substantial yields of iso-butane and normal butane,v sepyields of neo-hexane, and fractionating the prod-- ucts of the alkylation step to substantially separate the desired neo-hexane.

GUST 1V EGLOFF. 

